Health Articles

Ingestant or Food Allergy

The evaluation of the child who is suspected of having a food allergy can be fraught with unnecessary confusion because of misuse of terms. It is important to define the clinical syndrome to enhance understanding of the medical problem. An adverse food reaction is a generic term used to describe any untoward reaction following the ingestion of a food or food additive. Adverse food reactions can be categorized into food allergy (food hypersensitivity) or food intolerance. A food allergy is an abnormal immunologic response. A food intolerance is due to a nonimmunologic mechanism, such as toxins contained in the food, metabolic disorders (eg, disaccharidase deficiencies), or idiosyncratic reactions. Lactose intolerance due to lactase deficiency, a common cause of cow milk intolerance, often is mislabeled as milk allergy.

In addition, patients may experience a nonimmune adverse reaction to a constituent in food, such as monosodium gluconate added to food during processing, spices such as peppers (capsacian) added as flavoring during cooking, or preservatives. Although food additives, such as coloring or preservatives, may induce urticaria and, rarely, systemic allergy, the hypothesis that they contribute to behavior problems such as hyperactivity or other entities such as learning disabilities has never been substantiated in well-designed and controlled studies.

Symptoms other than those of the gastrointestinal system can result from allergic reactions to food. Anaphylactic reactions, fatal and near-fatal, have been reported both in children and adults. Anaphylactic shock associated with exercise following ingestion of certain foods has been reported in individuals, even though neither food nor exercise alone induced anaphylaxis. Ingestion or contact with food is a common cause of acute urticaria or angioedema. Chronic (>6 weeks’ duration) urticaria secondary to food allergy is much less common. Atopic dermatitis in infants and children commonly is associated with food allergy, especially from eggs, milk, wheat, peanuts, and fish.

Within 10 to 60 minutes after ingestion of a food allergen, some children may develop a pruritic, erythematous morbilliform rash. It has been postulated that repeated ingestion of the offending allergen leads to continuation of the IgE inflammatory response, which provokes the pruritus, scratching, and development of eczematous lesions of atopic dermatitis. Although not common, both upper and lower respiratory tract symptoms also have been described secondary to food allergy; however, respiratory symptoms associated with food allergy in the absence of gastrointestinal or skin symptoms is unusual.
Allergies articles